Fluid-pressure-operated tool.



FLUID PRESSURE OPERATED TOOL.

H mlll N0 MODEL.

UNITED STATES Patented November 3, 1903.

HENRY II. VAUGHAN AND CHARLES HARRIS JOHNSON, OF CHICAGO, ILLINOIS.

FLUID-PRESSURE-OPERATED TOOL.

sPEcIFIcA'rIoN forming part of nemers Patent No. 742,934, dated November s, 1903.

Application led January 14, 1902. Serial No. 89.751. (No model.)

To @ZZ whom it may concern,.-

Be it known that we, HENRY H. VAUGHAN and CHARLES HARRIS JOHNSON, citizens of the United States, residing at Chicago, county of Cook, State of Illinois, have invented a certain new and useful Improvement in Fluid- Pressure-Operated Tools; and We declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it pertains to make and use the same, reference being had to the accompanying drawings, which form a part of this specification.

Our invention relates in general to fluidpressure-operated tools, and more particularly to pneumatic hammers of the valveless type.

In iluid-pressure-operated tools as ordinarily constructed the piston delivers a blow upon a snap or shank of the tool immediately before reaching one end of its stroke, the initial propulsion of the piston toward the tool being due to the liow of fluid-pressu re from the source of motive-Huid supply, while the final portion of the stroke is due to the expansion of the fluid within the cylinder after the source of supply has been cut oif. Fluidpressure-operated tools have also been constructed heretofore Vin'which impetus is given to the stroke of the piston by placing in communication with the cylinder a reservoir which has been charged with pressure coincidently with the admission of pressure to the working end of the cylinder from the motiveuid supply; but itis obvious that in a tool so constructed the time available for charging the reservoir is limited to the time the induction-port remains open to the working end of the cylinder, and it is also obvious that the induction-port must remain open sufficiently long to charge the reservoir, as well as the working end of the cylinder, in order to avoid the reduction of the pressure in the working end of the cylinder at the beginning of the piston-stroke.

The primary object of our invention is to provide a fluid pressure operated tool in which the beginning of the stroke of the piston toward the tool is eiIected by the admission of pressure from the source of motive fluid, while the continuation of the pistonstroke is effected by connecting the working end of the cylinder with a reservoir which has been charged with pressure from the Inotive-fluid supply prior to the admission of pressure to the Working end of the cylinder.

A further object of ourinvention is to provide a tool of the class described which will be simple in construction and efficient in operation.

Our invention, generally stated, consists in a cylinder in which a piston reciprocates and a reservoir which is charged with pressure from the motive-fluid source during the throw of the piston away from the tool before the admission of pressure to the working end of the cylinder and which discharges into the cylinder after the piston has commenced its stroke toward the tool.

Our invention Will be more fully described hereinafter with reference to the accompanying drawings, and in which the same is illustrated as embodied in a convenient and practical form, and in Which'- Figure 1 is a longitudinal section through a tool embodying our invention, showing the piston delivering a blow upon the tool; and Fig. 2 isasimilar View showing the piston at the beginning of its stroke toward the tool..

The same reference characters are used in the two figures of the drawings to indicate the same parts.

Referenceletter A indicates a cylinder within which the piston D reciprocates. A handle B is secured to one end of the cylinder in any suitable manner. In the present instance a fiange B overlaps the end of the cylinder and is held in such position by a cap A, which is provided with a screwthreaded tubular portion a' in engagement with the interior surface of the end of the cylinder. A flange b', formed on the handle B, is interposed between the head of the cap A and the end of the cylinder A. Any suitable means may be provided for retaining the cap A' from rotation with respect to the handle, such means being shown as consisting in a spring-actuated bolt 67, engaging with ratchet-teeth on the rim of the cap A'.

A throttle-valve TB5 is located within a roo valve-seat B6, which is screwed into a tubular extension on the handle B, such valve controlling ports b5 through the valve-seat.

B4 indicates a coupling to which a pipe leading from the motive-fluid supply is secured.

B3 indicates a reciprocating spindle which at one end engages the throttle-valve B5 and at its other end is engaged by a hand-operated lever B2, pivotally mounted in the hand e B.

b indicates a passage in the handle B, communicating at one end with a passage controlled bythe throttle-valve and its other end in register with a passage a in the cylinder A. Au annular chamber A3, formed in` the cylinder, com municates with the other end of the passage d. A chamber A5 is provided in the end of thecylinder opposite to the handle B, such chamber communicating with the atmosphere through exhaust-ports a5. A lferrule Eis iitted within the end of the cylinder adjacent to the chamber A5, in which a die or snap or the shank of a tool F is 1ocated. A bushing C is preferably located within the cylinder A between the cap A and the annular chamber A3. Series of ports c' c2 c5 are formed through the bushing C and communicate with a chamber A2, formed in the cylinder A around the bushing. The series of ports c5 are formed through the bushing between its closed end and the cylinder-cap A.

The piston D is of a differential type and is provided with a shoulder d', formed between the main portion of the piston and the enlarged end thereof, D. The rpiston is preferably hollow and provided with ports d, extending from the interior thereof to the outer surface and located adjacent to the end of the piston opposite to the enlarged portion D. The reduced portion of the piston D is of such a diameter as to closely fit 'the inner surface of the portion A4 which extends between the annular chamber A3 and exhaust-chamber A5. The surface of the enlarged portion D closely tits within the interior of the bushing U and is sufficient to -simultaneously close both of the series of ports c and c2 through the bushing C.

It will be obvious from the drawings that the various parts of the tool may be assembled by introducing the bushing C .prior to inserting the cap A, so that an annular shoulder c4 on the exterior of the bushing will engage the wall at the end of the chamber A2, While the opposite end of the bushing will be engaged by the end of the screw-threaded collar a of the cap A. The cap A is inserted in theproper position with respect to the han-` die B prior to screwing into the end of the cylinder A.

The operation of our improved fluid-pressure-operated tool is as follows: The handlele'ver B2 is depressed, as indicated in Fig. 2, which through the interposed spindle B3 depresses the throttle-valve B5, so that the latter uncovers the ports b5. `Motive fluid consequently Hows from the source thereof through the coupling B4, thence through the ports b5 to the passage b, which registers with the passage a, which in turn communicates with the annular chamber A3. Thepiston D being in the position indicated in Fig. l, the motive fluid is exerted upon the shoulder d and causes the piston to move toward the handle,

inasmuch as the larger end of the piston and also the cylinder and chamber A2 therein are in communication with the atmosphere through the exhaust-ports d, the chamber A5, and the ports a5. When'in the movement of the pistou toward the handle the enlarged portion D' uncovers the ports o', motive tiuid is admitted through such ports'to the chamber A2 and also through the series of ports c3 to the space between the cap A and the end of the bushing C. The ohamberA2 and spacejwithin the cap A serve 'as a reservoir, which is charged with motive fluid through the ports c' during the interval'when the enlarged portion D of the piston moves the distance between the vpoint where it uncovers the ports c' and the end ot' its stroke toward the handle. length than the distance between the two series of ports c and c2, when the former is uncovered the latter is closed, so that motive uid cannot be admitted through them to the Working end of the cylinder. The piston continues in its stroke toward the handle 'B until the ports d register with the annular chamber A, as illust-rated in Fig. 2, at which time motive fluid is admitted through the ports d to the interior of the piston and thence to the working end of the cylinder, which in the present embodiment of my invention consists in the closed end Yof the bushing C. The greater area of the larger end of the piston is consequently subjected to pressure, and the piston immediately commences its stroke toward the tool. The communication with the motive iiuid is cut oi as soon as the ports cl pass out of register with the annular chamber A8, which occurs before the enlarged end D of the piston uncovers the series of ports c2. through the bushing; As soon as the ports c2 are uncovered the pressurewhich has been stored in the reservoir, consisting in the chamber A2 and space in the hollow cap A, discharges into the working end of the cylinder and adds impetus to the stroke of the piston. Upon the ports d being uncovered by the chamber A5 the working end'of the cylinder exhausts through the ports a5, and the stroke of the piston in the .opposite directionnamely, toward the handle-commences by reason of the motive duid being exerted upon the shoulder d'.

From the foregoing description it will be observed that the stroke of the piston toward the tool is commenced by motive iiuid admitted through the piston to the working end of the cylinder, while the stroke of the piston during that portion of its travel when the As the enlarged portion D is greater in IOC IIO

ports d are closed by the restricted interior surface A4 of the cylinder is effected not merely by the expansion ot' the motive fluid which has been admitted directly to the working end of the cylinder from the supply, but also by the expansion into the cylinder of the motive fluid which has been charged in the reservoir prior to the admission of the motive tluid from the supply to the cylinder. By connecting the reservoir with the supply during the interval ofthe time occupied by the enlarged portion of the piston D passing from the series of ports c' to the end of its stroke the reservoir is completely charged directly from the supply and only discharges into the working end of the cylinder after the stroke of the piston toward the tool has commenced by the admission of motive iiuid through the ports d to the working end of the cylinder. It is also evident that by admitting the motive fluid through the relatively large ports d to theworking end of the cylinder the entire expansibility of the fluid is utilized to impart initial movement to the piston and is not diminished by expansion from the working end of the cylinder into the reservoir.

While we have described more or less precisely the details of construction, we do not wish to be understood as limiting ourselves thereto, as We contemplate changes in form, the proportion of parts, and the substitution of equivalents as circumstances may suggest or render expedient without departing from the spirit of our invention.

Having now fully described our invention, what We claim as new, and desire to secure by Letters Patent, is-

1. In a duid-pressure-operated tool,the combination with a cylinder, of a reciprocating piston therein, a reservoir, means for charging said reservoir prior to the admission of pressure to the working end of the cylinder and means for connecting said reservoir directly with the working end of the cylinder after'the supply has been cut off, substantially as described.

2. In afluid-pressure-operated tool,the combination with a cylinder, of a reciprocating piston therein, a reservoir, said cylinder having a supply-port and ports communicating with said reservoir controlled by the piston to connect said reservoir with the motive-duid supply prior to the admission of fluid-pressure to the working end of the cylinder and to connect said reservoir with the working end of the cylinder after the motiveuid supply has been cut off, substantially as described.

3. In a fluid-pressure-operated tool,the combination with a cylinder having supply and exhaust ports, of a reciprocating piston in said cylinder controlling said ports, a reservoir having separate supply and discharge ports controlled by the piston the former port adapted to be connected to the motive-fluid source prior to the admission of pressure to the working end of the cylinder and the latter port adapted to be connected to the working end of t-he cylinder subsequent to the cutting o of the supply thereto, substantially as described.

4. In a tluid-pressure-operated tool,the combination with a cylinder having a Working chamber and a reduced bore, of a reciprocatingpiston fitting Within said reduced bore and having an enlarged portion fitting Within the Working chamber, a reservoir having a port adapted to be uncovered and thereby connected with the source of supply by the enlarged portion of the piston during its stroke away from the tool and a separate port communicating with the Working end of the cylinder adapted to be uncovered by said enlarged portion of the piston during its stroke toward the tool, substantially as described.

5.' In a iiuid-pressure-operated tool,the combination with a cylinder having a working chamber and a reduced bore, of a reciprocating piston tting within said reduced bore and having an enlarged portion tting within the workin g chamber, a reservoir having separate supply and discharge ports spaced apart a distance less than the length of said enlarged portion of the piston the former port adapted to be connected with the motiveiiuid source prior to the admission of pressure to the working end of the cylinder and the latter port adapted to be connected to the working end of the cylinder subsequent to the cutting o of the'supply, substantially as described.

6. In a duid-pressure-operated tool,the combination with a cylinder having supply and exhaust ports,of a bushinghaving ports therethrough within said cylinder,a reservoir between said bushing and said cylinder, a reciprocating piston within said cylinder controlling the supply and exhaust ports and having a portion fitted Within said bushing and controlling the ports therethrough Whereby pressure is admitted to said reservoir from the source of motive iiuid prior to the admission of pressure to the working end of the cylinder, substantially as described.

7. In a tluid-pressure-operated tool, the combination with a cylinder having an open end, of a bushing the exterior diameter of which is slightly less than the diameter of the open end of the cylinder, a cap secured Within the open end of the cylinder and engaging an end of said bushing, and a handle secured to the cylinder by said cap, substantially as described.

8. Inaduid-pressure-operatedtool,thecom bination With a cylinder having an open end, of a bushing tting within said cylinder and having an exterior diameter less than the interior diameter of the cylinder around the bushing thereby forming a storage-space between the cylinder and bushing,.a partition Within said bushing adjacent to one end thereof, a cap having a hollow chamber extending within the open end of said cylinder, said bushing having openings therethrough com- IIC reservoir having ports communicatingtherewith adapted to be uncovered by said shoul der and thereby connected with said annular chamber prior to the admission of pressure to the working end of the cylinder, substantially as described.

In testimony whereof we sign this specification in the presence of two witnesses.

HENRY H. vAUGHAN. CHARLES HARRIS JOHNSON.

VVitnesses:

GEO. L. WILKINSON, CLARA C. CUNNINGHAM. 

